1. Field of the Invention
The present invention relates in general to printed circuit boards and flex circuits (flexible printed circuit boards). More particularly, the present invention relates to a method and apparatus for serializing printed circuit boards and flex circuits during the manufacture of such boards and circuits.
2. Description of the Prior Art
The drive toward miniaturization in the electronics industry has resulted in the need to install a greater number of electronic components and conductive leads or strips in a given area on a printed circuit board or flex circuit. This miniaturization sometimes results in a decrease in the reliability and an increase in the failure rate of the printed circuit boards and flex circuits. Various steps have been attempted in an effort to improve the reliability and decrease the failure rate of the boards and circuits. One such step is the serializing (providing serial numbers or other identifying markings) of the printed circuit boards or flex circuits so they may be traced regarding such items as manufacturing line, component suppliers, test specifications and results, etc.
In the past, attempts have been made to serialize the printed circuit boards and flex circuits by incorporating the serialization information in the photomasks used in the conventional screening or print-and-etch techniques used to layout and produce the terminals and conductive leads or strips of the printed circuit boards or flex circuits. To provide different serialization or serial numbers for each different printed circuit board or flex circuit, a different photomask must be made for each printed circuit board or flex circuit or each board or circuit will contain the identical serial number.
Since it is not economically feasible to provide a different photomask for each printed circuit board or flex circuit, other methods have been attempted in providing the desired serialization. One such method is the use of labels which contain the serialization information and which are glued onto the printed circuit board or flex circuit after the terminals and conductive leads or strips have been formed on the boards or circuits. Another method is the writing of the serial number directly onto the finished printed circuit board or flex circuit.
The present invention is intended to provide a solution to various prior art deficiencies which include the inefficiency and high cost associated with the preparation of a different photomask for each printed circuit board or flex circuit. The man hours required for the gluing of labels containing serial numbers or the painting of serial numbers on the individual printed circuit boards or flex circuits increases the manufacturing cost of the boards or circuits. Also, the labels and painted serial numbers may be damaged during subsequent manufacturing processes and work-overs associated with the boards or circuits.